Global Systems

Atmosphere

The layer of gases surrounding Earth (includes weather and climate systems).

Biosphere

All living organisms on Earth (plants, animals, humans, microbes).

Geosphere

The solid part of Earth (rocks, soil, mountains, landforms).

Hydrosphere

All water on Earth (oceans, lakes, rivers, groundwater, ice).

Matter

(like water or carbon) can exist in and move between multiple spheres.

Troposphere

Weather occurs here; closest to Earth.

Stratosphere

Contains the ozone layer.

Mesosphere

Coldest layer; meteors burn up here.

Thermosphere

Very thin air; auroras occur.

Exosphere

Outermost layer; merges with space.

Earthquakes

Disrupt the geosphere, can release gases (atmosphere) and affect humans/animals (biosphere).

Volcanoes

Release ash and gas (atmosphere), alter landscapes (geosphere), and impact ecosystems (biosphere).

Cyclones

Involve intense atmospheric pressure systems that cause flooding (hydrosphere), damage to land (geosphere), and harm to communities (biosphere).

Photosynthesis

Plants absorb CO₂.

Respiration

Organisms release CO₂.

Decomposition

Dead organisms release carbon to soil and air.

Combustion

Burning of fossil fuels releases CO₂.

Fossilisation

Formation of fossil fuels from dead organisms.

Diffusion

CO₂ moves between ocean and air.

Consumption

Animals eat plants and transfer carbon.

Carbon moves through: Atmosphere

(CO₂ gas)

Carbon moves through: Biosphere

(plants/animals)

Carbon moves through:Geosphere

(fossil fuels, soil)

Carbon moves through: Hydrosphere

(dissolved CO₂)

Nitrogen fixation

Bacteria convert nitrogen gas to usable forms.

Nitrification

Ammonia is converted to nitrates/nitrites.

Assimilation

Plants absorb nitrogen from soil.

Consumption

Animals eat plants, obtaining nitrogen.

Ammonification

Decomposers convert waste to ammonia.

Denitrification

Bacteria convert nitrates back to nitrogen gas.

Nitrogen moves through: Atmosphere

(N₂ gas)

Nitrogen moves through:Biosphere

(organisms needing nitrogen for proteins/DNA)

Nitrogen moves through: Geosphere

(soil nitrogen compounds)

Nitrogen moves through: Hydrosphere

(aquatic nitrogen)

1. Carbon dioxide (CO₂)

A greenhouse gas produced through natural processes like respiration and decomposition, as well as human activities like burning fossil fuels and deforestation. It is the primary driver of climate change due to its abundance and heat-trapping properties.